An electronic component mounting system which manufactures a mounted board by mounting electronic components on the board is formed by combining a plurality of component mounting devices which mount the electronic components on the board on which paste for solder bonding was printed. In recent years, in the electronic industry, with the development of the diversification of production patterns, the production pattern in which multiple types of products are manufactured in a limited quantity is also increasingly applied in the field of component mounting. Therefore, in the component mounting system, the frequency of device type changing operations with the change of the type of the board which is a working object increases. Various schemes are proposed to effectively perform device type changing operations for the purpose of improving the productivity in the production field of the component mounting (for example, refer to a patent document 1). In the prior art shown in the patent document, a preparation mode in which an operator performs device type changing operations can be selected other than a mounting mode in which mounting operations are performed, and in the preparation mode, even if a moving part detects an obstacle or it is detected that the opening and closing cover of a device is opened, the power supplying part will be kept in an ON state. Therefore, there is an effect that it is not necessary to perform a resetting operation at the time of resuming mounting operations after the preparation operation is finished.